Re: HEAD and namespaces
- Date: Tue, 21 May 2019 17:46:30 -0400
- From: Jeff King <peff@xxxxxxxx>
- Subject: Re: HEAD and namespaces
On Mon, May 20, 2019 at 07:59:03PM -0700, Bryan Turner wrote:
> When using GIT_NAMESPACE, it appears the "symref" added to the
> capabilities advertisement doesn't get the namespace stripped. The
> namespace is stripped for the advertised refs, including "HEAD", but
> not on the "symref".
> Lafiel:test bturner$ GIT_NAMESPACE=foo GIT_TRACE_PACKET=1 git ls-remote origin
> 19:51:54.012696 pkt-line.c:80 packet: git<
> b9acca03606d4c674be8b7e79cd788cedbec957c HEAD\0multi_ack thin-pack
> side-band side-band-64k ofs-delta shallow deepen-since deepen-not
> deepen-relative no-progress include-tag multi_ack_detailed
Yeah, that seems totally broken. It's neat that we find HEAD inside the
namespace. But I think there are two bugs here:
1. We must call it "HEAD" and not the nonsense
2. We need to similarly remove the namespace from its contents. I
suppose it's possible that somebody stores the already-truncated
name in the symref, but as you noted then such a symref would be
totally broken from the perspective of the non-namespaced repo.
> I don't know whether the client somehow does some stripping on the
> "symref" to decide that HEAD should be
> "refs/namespaces/foo/refs/heads/master", but I'd assume not.
I don't think it can. It has no idea that namespaces are in play at all
(and the point of the feature is for it to be invisible to the client).
> Is this a bug? An oversight? An intentional decision? How is HEAD
> supposed to work when using GIT_NAMESPACE? Perhaps the expectation is
> that namespaces won't have their own HEADs? I'd say perhaps it's that
> even in the namespace the target ref shouldn't be namespaced, but that
> doesn't seem like it could possibly be correct since the namespace
> could contain refs that don't exist outside it, so Git would see the
> symbolic ref as broken.
I think it should be doing:
diff --git a/upload-pack.c b/upload-pack.c
index 24298913c0..4d2129e7fc 100644
@@ -1037,8 +1037,8 @@ static int find_symref(const char *refname, const struct object_id *oid,
symref_target = resolve_ref_unsafe(refname, 0, NULL, &flag);
if (!symref_target || (flag & REF_ISSYMREF) == 0)
die("'%s' is a symref but it is not?", refname);
- item = string_list_append(cb_data, refname);
- item->util = xstrdup(symref_target);
+ item = string_list_append(cb_data, strip_namespace(refname));
+ item->util = xstrdup(strip_namespace(symref_target));
and this case has just been broken since 7171d8c15f (upload-pack: send
symbolic ref information as capability, 2013-09-17). It mostly works
because of fallback to the old guessing behavior, so nobody really
noticed. (I also suspect namespaces are not widely used at all, but I
could be wrong).